The primary aim for this project is to assemble a microcomputer-controlled system for in vivo electrochemical measurements of catecholamine-related compounds in striatum. Initial experiments will be conducted to examine changes in electrochemical signals following behavioral and pharmacological manipulations known to influence striatal catecholamine activity. While the technology for this type of experiment already exists for rodents, the extension of electrochemical detection to primates constitutes a significant advance in the basic mental health sciences. It is of particular importance to validate and apply these procedures in monkeys for the following reasons: (i) The size of the monkey and the monkey striatum offer the possibility for more precise experimental description of the relationship between well-defined behavioral or motor patterns and topologically specific chemical activation than is possible in the motorically limited and small-brained rodent. (ii) Electrochemical detection is a potential means of obtaining larger quantities of behaviorally related data than can be gotten through use of techniques requiring immediate sacrific of the animals. (iii) The behavioral and chemical data obtained will be more relevant to human behavioral problems than data from rodents, because of the marked behavioral and neurophysiological similarities between monkey and humans.